* {
    /* border 三个参数  边框宽度   边框形状   边框颜色*/
    margin: 0;
}

.home {
    display: flex;
    justify-content: center;
}

/*    div 元素选择器*/
/*注释  不显示在页面,用来解释代码的意思*/
div {
    /*border: 1px solid red;*/
}

/* class 类选择器*/
.top {
    /*border: 1px solid red;*/
    background-image: url("../img/banner_qtah.jpg");
    /*100%表示和当前div的外层div的高宽一致*/
    /* 1920 808*/
    width: 1000px;
    /*height: calc(808px * 1000 / 1920);*/
    height: 500px;
    background-size: 100% 100%;

}

.content-width {
    width: 1000px;
    /*margin: auto;*/
}

.top {
    color: white;
}

/*-------------头部 公司介绍---------------------*/
.top > div:nth-child(1) {
    display: flex;
    justify-content: center;
    height: 141px;
}

.top > div:nth-child(1) > div {

    display: flex;
    width: 900px;
    justify-content: space-between;
}

.top > div:nth-child(1) > div > div:nth-child(2) {
    display: flex;
    align-items: center;
}

.top > div:nth-child(1) > div > div:nth-child(2) > div {
    margin-right: 10px;
}

.top > div:nth-child(1) > div > div:nth-child(2) > div:nth-child(2) {
    margin-top: -5px;
}

/* 头部  导航 */
.top > div:nth-child(2) {
    background-color: rgb(230, 145, 55);
    height: 40px;
    display: flex;
    justify-content: center;

}

.top > div:nth-child(2) > div {
    width: 900px;
    display: flex;
}

.top > div:nth-child(2) > div > div {
    height: 40px;
    line-height: 40px;
    /*margin:  0 20px;*/
    padding: 0 20px;
}

.top > div:nth-child(2) > div > div:hover {
    background-color: white;
    color: rgb(230, 145, 55);
    cursor: pointer;
}

/*-----------------头部  广告-------------------*/
.top > div:nth-child(3) {
    display: flex;
    justify-content: center;
}

.top > div:nth-child(3) > div {
    /*border: 1px solid red;*/
    height: 300px;
    width: 900px;
}

.ad > div:nth-child(1) {
    padding: 20px 0 0 0;
    font-size: 40px;
}

.ad > div:nth-child(2) {
    font-size: 10px;
    line-height: 20px;
}

bb {
    font-size: 20px;
    color: rgb(230, 145, 55);
    margin-right: 20px;
}

/*bb:nth-child(3){*/
/*    text-indent: 3em;*/
/*}*/
.ad > div:nth-child(3) > div:nth-child(2) {
    text-indent: 3em;
}

/*--------------------------公共的css-------------*/
.title {
    font-size: 30px;
    color: rgb(230, 145, 55);
    padding: 10px;
}

.middle {
    display: flex;
    justify-content: center;
}

.middle > div {
    width: 900px;
    margin: 50px 0;
}
